Parkinson's can start in bed, say researchers who claim to have found evidence that acting out in dreams -- like kicking or punching -- may actually be a warning sign for early onset of the disease.

Parkinson's can start in bed, say researchers who claim to have found evidence that acting out in dreams -- like kicking or punching -- may actually be a warning sign for early onset of the disease.

An international team, led by the University of Sydney, has claimed that "those things that go bump or kick in the night" may actually be signalling the early onset of Parkinson's disease.

According to lead researcher Dr Simon Lewis, people don't realise that the disease can have many different early manifestations.

"Interestingly, although best known for its physical symptoms like slowness and tremor, Parkinson's disease is often preceded by a host of seemingly unrelated symptoms like mood change, loss of smell, constipation and sleep disorders.

"Possibly the most dramatic of its symptoms is known as Rapid Eye Movement Sleep Behaviour Disorder. Parkinson patients have been known to start acting out in their dreams, often punching or kicking the person sharing their bed.

"For some Parkinson patients it comes as a revelation and relief, not to mention their spouses, that the condition may be responsible for things that go 'bump' or 'kick' in the night," he said.

Problems with thinking and memory are also common in Parkinson's diseases with patients being six times more likely to be diagnosed with dementia, say the researchers.

"We believe the disease spreads slowly through the brain and these non-physical symptoms can often predate the disease by many years, potentially offering an early way of recognising the condition," said Dr Lewis.